Tropical Storm HUMBERTO

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TROPICAL STORM HUMBERTO DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013
1100 AM AST MON SEP 09 2013
VISIBLE SATELLITE IMAGERY INDICATES THAT HUMBERTO STILL HAS AN
ELONGATED LOW-LEVEL CIRCULATION...WITH THE CENTER NEAR THE EASTERN
EDGE OF THE DEEP CONVECTION. THIS WAS CONFIRMED BY TWO ASCAT
PASSES FROM EARLIER THIS MORNING...BUT THE SCATTEROMETER DATA ALSO
INDICATED THAT MAXIMUM WINDS HAVE INCREASED TO 40 KT. THIS
ESTIMATE IS ALSO SUPPORTED BY AN AVERAGE OF THE DVORAK ESTIMATES
FROM TAFB AND SAB.
HUMBERTO IS LOCATED TO THE SOUTH OF A STRONG AZORES HIGH AND
CONTINUES TO MOVE 280/10 KT. THE TRACK FORECAST THINKING HAS NOT
CHANGED. THE RIDGE IS EXPECTED TO WEAKEN DURING THE NEXT 48
HOURS...GIVING WAY TO TWO CLOSED MID/UPPER-LEVEL LOWS THAT WILL
DEVELOP NORTH OF THE CANARY ISLANDS AND OVER THE CENTRAL ATLANTIC.
THIS PATTERN SHOULD CAUSE HUMBERTO TO TURN SHARPLY NORTHWARD BY DAY
3. AFTER THAT TIME...HIGH PRESSURE AGAIN BUILDS NEAR THE
AZORES...FORCING HUMBERTO TO TURN BACK TO THE WEST-NORTHWEST BY DAY
5. THE GLOBAL MODELS ARE TIGHTLY CLUSTERED THROUGH THE FIRST 48
HOURS BUT THEN DIVERGE WITH THE GFS...FLORIDA STATE
SUPERENSEMBLE...GFDL...AND HWRF INDICATING A SHARPER TURN TOWARD
THE NORTH. THE GUIDANCE SUPPORTS A SLIGHT NORTHEASTWARD SHIFT FROM
THE PREVIOUS FORECAST AT THE LATTER END OF THE FORECAST PERIOD.
THE EAST-NORTHEASTERLY SHEAR AFFECTING HUMBERTO IS EXPECTED TO ABATE
WITHIN THE NEXT 12 HOURS...AND THE THERMODYNAMICS APPEAR
SUFFICIENTLY CONDUCIVE TO SUPPORT ADDITIONAL INTENSIFICATION DURING
THE NEXT 72 HOURS. THE SHIPS AND LGEM MODELS CONTINUE TO SHOW THE
MOST AGGRESSIVE STRENGTHENING...BUT THAT IS COUNTERED BY THE
HWRF...GFDL...AND FLORIDA STATE SUPERENSEMBLE WHICH EITHER DO NOT OR
JUST BARELY MAKE HUMBERTO A HURRICANE. THE OFFICIAL FORECAST STILL
LIES BETWEEN THESE TWO SCENARIOS AND IS JUST A TAD HIGHER THAN THE
INTENSITY CONSENSUS. THE OFFICIAL FORECAST IS GENERALLY AN UPDATE
OF THE PREVIOUS ONE...AND IS UNCHANGED FROM DAYS 3 THROUGH 5.
FORECAST POSITIONS AND MAX WINDS
INIT 09/1500Z 13.6N 24.1W 40 KT 45 MPH
12H 10/0000Z 13.9N 25.5W 50 KT 60 MPH
24H 10/1200Z 14.5N 27.3W 60 KT 70 MPH
36H 11/0000Z 15.5N 28.5W 70 KT 80 MPH
48H 11/1200Z 17.3N 29.1W 75 KT 85 MPH
72H 12/1200Z 21.5N 30.0W 80 KT 90 MPH
96H 13/1200Z 24.5N 31.0W 70 KT 80 MPH
120H 14/1200Z 26.0N 34.5W 60 KT 70 MPH
$$
FORECASTER BERG/PASCH
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